U.S. patent number 7,765,835 [Application Number 11/719,116] was granted by the patent office on 2010-08-03 for elastic composite yarn, methods for making the same, and articles incorporating the same.
This patent grant is currently assigned to Textronics, Inc.. Invention is credited to Philippe Chaudron, George W. Coulston, Eleni Karayianni.
United States Patent |
7,765,835 |
Karayianni , et al. |
August 3, 2010 |
**Please see images for:
( Certificate of Correction ) ** |
Elastic composite yarn, methods for making the same, and articles
incorporating the same
Abstract
An elastic composite yarn comprises a composite core and a
composite covering. The composite core comprises an elastic core
member and an inelastic functional core member. The composite
covering comprises at least an elastic covering member and at least
one inelastic covering member surrounding the elastic covering
member, such that substantially all of an elongating stress imposed
on the composite yarn is carried by the elastic core member and the
elastic covering member.
Inventors: |
Karayianni; Eleni (Geneva,
CH), Chaudron; Philippe (Sant Julien en Genevois,
FR), Coulston; George W. (Pittsburgh, PA) |
Assignee: |
Textronics, Inc. (Wilmington,
DE)
|
Family
ID: |
35636876 |
Appl.
No.: |
11/719,116 |
Filed: |
November 8, 2005 |
PCT
Filed: |
November 08, 2005 |
PCT No.: |
PCT/IB2005/003345 |
371(c)(1),(2),(4) Date: |
July 16, 2008 |
PCT
Pub. No.: |
WO2006/051384 |
PCT
Pub. Date: |
May 18, 2006 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20090071196 A1 |
Mar 19, 2009 |
|
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
60627168 |
Nov 15, 2004 |
|
|
|
|
Current U.S.
Class: |
66/172E |
Current CPC
Class: |
D02G
3/328 (20130101); D10B 2401/20 (20130101); Y10T
442/2377 (20150401) |
Current International
Class: |
D04B
1/18 (20060101) |
Field of
Search: |
;66/170,172E,202
;57/210,225,231 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
10342787 |
|
May 2004 |
|
DE |
|
0111070 |
|
Jun 1984 |
|
EP |
|
1 319 741 |
|
Jun 2003 |
|
EP |
|
2031797 |
|
Nov 1970 |
|
FR |
|
2 745 690 |
|
Sep 1997 |
|
FR |
|
2156592 |
|
Oct 1985 |
|
GB |
|
2361431 |
|
Oct 2001 |
|
GB |
|
WO-92/13352 |
|
Aug 1992 |
|
WO |
|
9516877 |
|
Jun 1995 |
|
WO |
|
WO-01/02052 |
|
Jan 2001 |
|
WO |
|
WO-01/37366 |
|
May 2001 |
|
WO |
|
WO-01/39326 |
|
May 2001 |
|
WO |
|
0212785 |
|
Feb 2002 |
|
WO |
|
02068862 |
|
Sep 2002 |
|
WO |
|
WO-02/071935 |
|
Sep 2002 |
|
WO |
|
WO-03/094717 |
|
Nov 2003 |
|
WO |
|
WO-2004/006700 |
|
Jan 2004 |
|
WO |
|
WO-2004/027132 |
|
Apr 2004 |
|
WO |
|
2004057079 |
|
Jul 2004 |
|
WO |
|
WO-2004/058346 |
|
Jul 2004 |
|
WO |
|
2004097089 |
|
Nov 2004 |
|
WO |
|
WO-2004100784 |
|
Nov 2004 |
|
WO |
|
Primary Examiner: Worrell; Danny
Attorney, Agent or Firm: Connolly Bove Lodge & Hutz
LLP
Claims
What is claimed is:
1. An elastic composite yarn comprising: a composite core and a
composite covering; wherein the composite core comprises: (a) an
elastic core member having relaxed unit length L and a drafted
length of (N.times.L), wherein N is in the range of about 1.0 to
about 8.0; and (b) an inelastic functional core member having a
fixed length of (N.times.L); and wherein the composite covering
comprises: (a) at least an elastic covering member; and (b) at
least one inelastic covering member surrounding the elastic
covering member; wherein the composite covering has a relaxed
length that is greater than the drafted length (N.times.L), of the
elastic core member, such that substantially all of an elongating
stress imposed on the composite yarn is carried by the elastic core
member and the elastic covering member.
2. The elastic composite yarn of claim 1, wherein the inelastic
functional core member is selected from the group consisting of:
stainless steel fibers, stainless steel yarns, plastic optical
fibers, silica fibers, glass fibers, and metallized aramid
fibers.
3. The elastic composite yarn of claim 1, wherein the inelastic
functional core member comprises a functional yarn having at least
one property selected from electrical, optical, and magnetic
properties.
4. The elastic composite yarn of claim 1, wherein the inelastic
functional core member has a modulus defined by (a) a force to
break of greater than 2N in an elongation limit of less than 20% or
(b) a yield point of greater than 2N in an elongation limit of less
than 20%.
5. The elastic composite yarn of claim 1, wherein the inelastic
covering member comprises a textile fiber selected from the group
consisting of: nylon, polyester, cotton, and wool.
6. The elastic composite yarn of claim 1, wherein the inelastic
covering member comprises a functional yarn having electrical,
optical or magnetic properties with a force to break or yield point
of less than 4 N.
7. The elastic composite yarn of claim 6, wherein the inelastic
covering member comprises a metal wire.
8. A method for forming an elastic composite yarn comprising: (1)
providing a composite core and a composite covering; wherein the
composite core comprises: (a) a first elastic member having relaxed
unit length L and a drafted length of (N.times.L), wherein N is in
the range of about 1.0 to about 8.0; and (b) an inelastic
functional member having a fixed length of N.times.L; and wherein
the composite covering comprises: (a) a second elastic member; (b)
and at least one inelastic member; (2) drafting the first elastic
member to a drafted length of (N.times.L); (3) placing the
inelastic functional member substantially parallel to and in
contact with the drafted length of the first elastic member; and
(4) wrapping, twisting, air jet covering, or core spinning in turns
the composite covering about the drafted first elastic member and
the inelastic functional member.
9. The method of claim 8, wherein the composite covering is wrapped
about the first elastic member and the inelastic functional member
in a relaxed state.
10. The method of claim 8, wherein the composite covering is
wrapped about the first elastic member and the inelastic functional
member under tension.
11. The method of claim 8, wherein the inelastic member of the
composite covering is wrapped in turns about the second elastic
member.
12. The method of claim 8, wherein the inelastic member of the
composite covering and the second elastic member are twisted
together.
13. The method of claim 8, wherein the second elastic member is air
jet covered by the inelastic member of the composite covering.
14. The method of claim 8, wherein the second elastic member is
core spun with the inelastic member of the composite covering.
15. A knitted or woven fabric comprising the elastic composite yarn
of claim 1.
16. A method for controlling bending of electrical or optical
fibers that are inelastic functional core member(s) in a composite
yarn in a fabric, comprising: (1) providing the fabric that
includes one or more elastic composite yarns, said elastic
composite yarns comprising a composite core and a composite
covering; wherein the composite core comprises: (a) an elastic core
member having relaxed unit length L and a drafted length of
(N.times.L), wherein N is in the range of about 1.0 to about 8.0;
and (b) an inelastic functional core member having a fixed length
of (N.times.L); and wherein the composite covering comprises: (a)
at least an elastic covering member; and (b) at least one inelastic
covering member surrounding the elastic covering member; wherein
the composite covering has a relaxed length that is greater than
the drafted length (N.times.L), of the elastic core member, such
that substantially all of an elongating stress imposed on the
composite yarn is carried by the elastic core member and the
elastic covering member; and (2) dynamically controlling bending or
looping of the inelastic functional core member by stretching and
relaxing the elastic composite yarn(s) in the fabric.
17. The method of claim 16, further comprising differentiated heat
setting the fabric.
18. A method for controlling bending of electrical or optical
fibers that are inelastic functional core member(s) in a composite
yarn in a fabric, comprising: (1) providing the fabric that
includes one or more elastic composite yarns, said elastic
composite yarns comprising a composite core and a composite
covering; wherein the composite core comprises: (a) an elastic core
member having relaxed unit length L and a drafted length of
(N.times.L), wherein N is in the range of about 1.0 to about 8.0;
and (b) an inelastic functional core member having a fixed length
of (N.times.L); and wherein the composite covering comprises: (a)
at least an elastic covering member; and (b) at least one inelastic
covering member surrounding the elastic covering member; wherein
the composite covering has a relaxed length that is greater than
the drafted length (N.times.L), of the elastic core member, such
that substantially all of an elongating stress imposed on the
composite yarn is carried by the elastic core member and the
elastic covering member; and (2) heat setting at least a portion of
the fabric to straighten at least some portions of the inelastic
functional core member(s) in the fabric.
Description
FIELD OF THE INVENTION
The present invention relates to elastified yarns containing high
modulus or low bending functional fibers, a process for producing
the same, and to stretch fabrics, garments, and other articles
incorporating such yarns. The invention also relates to novel
elastified yarns made via yarn covering processes in which at least
one covering member is, itself, an elastified yarn.
BACKGROUND OF THE INVENTION
Fabrics with functional properties have been disclosed for use in
textile yarns. Examples include metallic yarns that can be used for
carrying electrical current, performing an anti-static electricity
function, or providing shielding from electric fields. Such yarns
or fibers can, for example, include: multifilament stainless steel
yarns; metallized aramid fibers; optical fibers for transmitting
electrical data by acting as light waveguides; and glass or silica
fibers for dielectric high frequency applications, Such highly
functional yarns have been fabricated into fabrics, garments and
apparel articles.
It is generally considered to be impractical to base a textile yarn
solely on such high modulus filaments or on a combination yarn
where the high modulus filaments are required to be a flex member
of the yarn. Such high modulus filaments can typically be expected
to exhibit low bending capability and poor flexibility.
Sources of stainless steel continuous multifilament fibers
typically used in textiles include, but are not limited to: NV
Bekaert SA, Kortrijk, Belgium; and Sprint Metal Groupe Arcelor,
France. Depending on the number of filaments and the number of
twisted yarns involved, these yarns usually have a filament
diameter from about 6 .mu.m to about 12 .mu.m, and an electrical
resistivity in the range of about 2 Ohm/m to about 70 Ohm/m. In
general, these metal fibers exhibit a high force to break,
typically in the range of about 20 N to about 500 N and relativity
little elongation, typically less than about 5%. However, these
fibers exhibit substantially no elasticity. In contrast, many
elastic synthetic polymer based textile yarns stretch to at least
about 125% of their unstressed specimen length and recover more
than about 50% of this elongation upon relaxation of the
stress.
Sources of plastic optical fibers for use in textiles include, but
are not limited to: Toray Industries, Inc.; Mitsubishi Corporation;
and Asahi Chemical. Typically, these fibers have diameters of about
0.5 to about 2 mm. Due to their construction, such fibers have the
ability to transmit light along their length via total internal
reflection, which light can then be converted into electrical
energy or signals. This property of optical fibers tends to make
them advantageous as compared to metal wires or coaxial
transmission for data signal transmission, especially due to their
relatively higher bandwidth, lower attenuation, lower noise, and
lower cost.
Sources of metallized fibers include metallic coatings added on the
surface of aramid fibers, such as Aracon.RTM. manufactured and sold
by E.I. DuPont de Nemours. These yarns are based on stranded
Kevlar.RTM. fibers, having an equivalent diameter to metal wire of
about 54 AWG and electrical resistivity in the range of about 2
Ohms/m to about 9 Ohms/m. In general, these metallic fibers have a
load to break of about 27 N to about 70 N and an elongation to
break of less than about 5%.
Sources of inorganic quartz or silica fibers for use in textiles
include, but are not limited to those made by Saint-Gobain
(France). These fibers generally have filament diameters of about 1
.mu.m to about 25 .mu.m, a dielectric constant in the range of
about 3 to about 7 in the frequency range up to about 10 GHz, and a
loss tangent of about 0.0001 to about 0.0068 in the frequency range
up to about 10 GHz. In general, these fibers exhibit a high tensile
strength in the range of about 2000 N/mm.sup.2 to about 6000
N/mm.sup.2, high tensile modulus of about 50,000 N/mm.sup.2 to
about 90,000 N/mm.sup.2, and relativity little elongation of about
2 to about 8%.
State of the Art: Plastic Optical Fibers in Textiles
Woven fabrics made by incorporation of optical fibers are known in
the art. Typically, such optical fibers have an internal core and
an external sheath. The external sheath has a lower refractive
index compared to the internal core, which causes total internal
reflection of light so that light travels solely through the
internal core of the fiber. Light may be caused to escape from the
surface of the fiber, thus creating an illuminating effect. There
are two major directions disclosed for such effect: (1) attack of
the fiber surface (mechanical or chemical), (2) deformation or
bending of the fiber, at discrete locations along the fiber
length.
(1) State-of-the-art Illumination by Optical Fibers Via Mechanical
Attack
U.S. Pat. No. 4,234,907 to Maurice, discloses a light-emitting
fabric woven with optical fibers for use in clothing, interior, or
technical textiles. Optical fibers are woven in the warp direction
crossed with normal textile fibers as weft threads. The optical
fibers are illuminated at one end by a light source. Illumination
from the surface of the fiber is achieved by making notches at the
cladding till the inner core, the spacing of which becomes narrower
as the distance from the light source increases so that there is a
uniform distribution of light across the fabric. Analysis or such
fabric makes it unsuitable for industrial manufacturing, as the
notches weaken the fiber, making textile processing impossible,
while the bundling of all fiber ends into a light source would
require extreme fiber length extending out of the fabric.
WO 02/12785 A1 to Givoletti, discloses a textile incorporating
illuminated fibers. The fibers consist of a central core capable of
transmitting light and of an external sheath that presents a
refractive index, which in respect to the internal core, allows the
transmitted light to escape partially from the fiber. Illumination
is achieved by texturing the fibers (via e.g. abrasions,
scratching), adding doping elements inside the fiber that modify
the diffusion angle of light, modifying the refractive index of the
cladding so as to disperse the light along the fiber, and modifying
the reflective index of the optical fibers by fabric treatment
through mechanical or chemical means. Further the reference
discloses a special woven construction that illuminates light
uniformly.
WO 02/068862A1 to Deflin et al., discloses a lighting device based
on optical fibers with light-emitting segments, a possible
structure of such a device including optical fibers that are woven
into a textile together with other textile fibers. In 2002, France
Telecom won the Avantex Innovation Prize for the presentation of a
first flexible display based on an optical fiber fabric (E. Deflin,
et. al., "Communicating Clothes: Optical Fiber Fabric for a New
Flexible Display", 2.sup.nd International Avantex Symposium,
Frankfurt, Germany). Optical fibers were processed via a special
process of fiber surface mechanical attack, disclosed in
PCT/FR94/01475, to A. Bernasson, et al., allowing for light to be
scattered throughout the outer surface of the fibers at controlled
locations on the length of the fiber. The fibers were then woven
into a fabric. They were lighted through LEDs that could be used to
light groups of fibers, each group representing one pixel of the
matrix. By controlling the matrix through wireless
telecommunication services, various patterns can be generated in
the cloth, hence providing for an intelligent display. Although
fine fiber diameters were used (about 0.5 mm), it was not optimal
to create an X-Y network by introducing the fibers both in the weft
and warp directions, as the fabric would be very rigid and the grid
not very dense. Therefore, such fabrics would not be appropriate
for typical clothing applications, where flexibility and freedom of
movement of the fabric are of paramount importance. Further,
special processing of the fibers is needed to transmit light from
the surface of the optical fiber.
WO 2004/057079A1 to Laustsen, discloses a woven fabric with optical
fibers that goes beyond the disclosure of U.S. Pat. No. 4,234,907
by allowing optical fibers to extend in mutually crossing
directions in the fabric. According to the Laustsen reference, the
fabric is hot rolled to compress and flatten the light guides, and
further is laser treated to create partial ruptures at the surface
of the optical fibers.
(2) State-of-the-art Illumination by Optical Fibers Via Bending
U.S. Pat. Nos. 4,885,663, 4,907,132, 5,042,900, and 5,568,964 to
Parker et al., disclose fiber optic light emitting panel assemblies
made of woven optical fibers. Light is caused to be transmitted
from the optical fiber surfaces by deforming or bending the optical
fibers at discrete locations along their length such that the angle
of bend exceeds the angle of internal reflection. The optical
fibers are typically woven in the warp direction, while till
threads are woven in the weft direction, although the fill threads
are also allowed to be optical fibers. The output pattern of light
is achieved by controlling the weave spacing and pattern of the
optical fibers and fill threads. A portion of the light emitting
area is sealed by adhering the optical fibers and fill threads
together to hold the fill threads in position and keep the optical
fibers from separating from the light emitting portion.
UK 2,361,431A to Whitehurst, discloses a fiber optic fabric for
phototherapy, wherein light emitted from the surface of the optical
fibers (including plastic and glass optical fibers) is directed
towards a patient for the treatment of large area skin conditions
for therapy, or cosmetic treatment. The inventor found that by
weaving the optical fiber together with other fill yarns, the
optical fiber bending around the fill fibers causes light to be
refracted out of the optical fiber and hence out of the fabric. It
is disclosed that when a large number of optical fibers is woven in
this way, the fabric will emit light in a generally uniform
distribution across the fabric. For the use of the fabric for
phototherapy, it is very important that the fabric has flexibility
to provide the necessary movement and comfort for the user, and
that it follows the skin area that needs to be protected. However,
it is known that fabrics based on optical fibers are rigid and
tough for wearable clothing and wilt generally not allow movement
of the fabric in the direction of optical fibers. Therefore, such a
fabric may not provide for the desired flexibility or be optimum
for the intended application.
(3) State-of-the-art Optical Fibers for Signal Transmission
U.S. Pat. No. 6,381,482B1 to Jayaraman et al., discloses a tubular
knitted or woven fabric, or a woven or knitted 2-dimensional
fabric, including integrated flexible information infrastructure
for collecting, processing, transmitting, and receiving information
concerning a wearer of the fabric. The fabric consists of a base
fabric providing for wear comfort and an information component,
which includes sheathed plastic optical fiber to provide a
penetration detection means as well as data transferring
information. The fabric, consisting of the optical fibers, is then
integrated into a garment structure by joining techniques such as
sewing, gluing or attachment.
Optical fibers as sensors have also been used in textile composites
to distribute sensing locally (point) or multiplexed (multi-point)
exploiting intensiometric, interferometric, or Bragg grating
principles. See X. M. Tao, J. Text. Inst. 2000, Vol 91 Part 1, No.
3, pp 448-459; and W. C. Du et al., J. Compos. Struct. Vol 42, pp.
217-230, (1998). Optical fibers can provide an effective means to
determine quantitatively the distribution of physical parameters
(e.g., temperature, stress-strain, pressure), and therefore may
find uses in smart structures applications, such as monitors of
manufacturing processes and internal-health conditions. In these
developments, the embedded optical fibers also act as
signal-transmission elements.
Stretch and recovery is considered to be an especially desirable
property of a yarn, fabric or garment, which is also able to
conduct electrical current, transmit data processing information,
illuminate, sense, and/or provide electric field shielding. The
stretch and recovery property, or "elasticity", is the ability of a
yarn or fabric to elongate in the direction of a biasing force (in
the direction of an applied elongating stress) and return
substantially to its original length and shape, substantially
without permanent deformation when the applied elongating stress is
relaxed. In the textile arts, it is common to express the applied
stress on a textile specimen (e.g., a yarn or filament) in terms of
a force per unit of cross section area of the specimen or force per
unit linear density of the unstretched specimen. The resulting
strain (elongation) of the specimen is expressed in terms of a
fraction or percentage of the original specimen length. A graphical
representation of stress versus strain is the stress-strain curve,
which is well-known in the textile arts.
The degree to which a fiber, yarn, or fabric returns to the
original specimen length prior to being deformed by an applied
stress is called "elastic recovery". In stretch and recovery
testing of textile materials, it is also important to note the
elastic limit of the test specimen. The elastic limit is the stress
load above which the specimen shows permanent deformation. The
available elongation range of an elastic filament is that range of
extension throughout which there is no permanent deformation. The
elastic limit of a yarn is reached when the original test specimen
length is exceeded after the deformation inducing stress is
removed. Typically, individual filaments and multifilament yarns
elongate (strain) in the direction of the applied stress. This
elongation is measured at a specified load or stress. In addition,
it is useful to note the elongation at break of the filament or
yarn specimen. This breaking elongation is that fraction of the
original specimen length to which the specimen is strained by an
applied stress which ruptures the last component of the specimen
filament or multifilament yarn. Generally, the drafted length is
given in terms of a draft ratio equal to the number of times a yarn
is stretched from its relaxed unit length.
Elastic fabrics having conductive wiring affixed to the fabric for
use in garments intended for monitoring of physiological functions
in the body are disclosed in U.S. Pat. No. 6,341,504 to Istook.
This patent discloses an elongated band of elastic material
stretchable in the longitudinal direction and having at least one
conductive wire incorporated into or onto the elastic fabric band.
The conductive wiring in the elastic fabric band is formed in a
prescribed curved configuration, e.g., a sinusoidal configuration.
This elastic conductive band is able to stretch and alter the
curvature of the conduction wire. As a result, the electrical
inductance of the wire is changed. This property change is used to
determine changes in physiological functions of the wearer of a
garment including such a conductive elastic band. The elastic band
is formed in part using an elastic material, preferably spandex.
Filaments of the spandex material, sold by INVISTA.RTM. North
America Sa r. I., Wilmington, Del., under the trademark LYCRA.RTM.,
are disclosed as being a desirable elastic material. Conventional
textile means to form the conductive elastic band are disclosed,
including: warp knitting, weft knitting, weaving, braiding, and
non-woven construction. Other textile filaments, in addition to
metallic filaments and spandex filaments, are included in the
conductive elastic band. These other filaments include nylon and
polyester.
While elastic conductive fabrics with stretch and recovery
properties dominated by a spandex component of the composite fabric
band have been disclosed, these conductive fabric bands are
intended to be discrete elements of a fabric construction or
garment used for prescribed physiological function monitoring.
Although such elastic conductive bands may have advanced the art in
physiological function monitoring, they have not been shown to be
satisfactory for use in a way other than as discrete elements of a
garment or fabric construction.
In view of the foregoing, it is believed desirable to provide high
modulus functional textile yarns, including but not limited to
conductive, fiber optic, and glass fibers, wherein such textile
yarns have elastic recovery properties that can be processed using
traditional textile means to produce knitted, woven, or nonwoven
fabrics ("elastic functional yarns"). Further, it is believed that
there is yet a need for fabrics and garments that are substantially
constructed from such elastic functional yarns. Fabrics and
garments substantially constructed from elastic functional yarns
can provide stretch and recovery characteristics to the entire
construction, conforming to any shape, any shaped body, or
requirement for elasticity. It is further believed desirable to
provide controlled loops (bends) of such high modulus functional
fibers, either individually or within the fabric construction, so
as to provide for special illumination effects, as in the case of
optical fibers, or special electrical signals, as in the case of
conductive fiber loops for inductive signal generation and
transmission.
SUMMARY OF THE INVENTION
The present invention is directed to an elastic composite yarn
comprising (a) a composite core member and (b) a composite covering
member, wherein the composite core member comprises: (i) an elastic
core member having relaxed unit length L and a drafted length of
(N.times.L), wherein N is in the range of about 1.0 to about 8.0;
and (ii) an inelastic functional core member having a fixed length
of (N.times.L). The composite covering member comprises (i) at
least one elastic covering member. Preferably, the composite
covering member further comprises (ii) at least one inelastic
covering member surrounding the elastic covering member. The
composite covering member has a relaxed length that is greater than
the drafted length (N.times.L) of the elastic core member, such
that substantially all of an elongating stress imposed on the
composite yarn is carried by the elastic core member and the
elastic covering member.
The present invention is also directed to methods for forming an
elastic composite yarn. One method includes the step of first
providing (a) a composite core and (b) a composite covering,
wherein the composite core comprises: (i) a first elastic member
having relaxed unit length L and a drafted length of (N.times.L),
wherein N is in the range of about 1.0 to about 8.0; and (ii) an
inelastic functional member having a fixed length of N.times.L; and
the, composite covering comprises (i) a second elastic member and
(ii) at least one inelastic member. Further steps of the method
include: drafting the first elastic member to a drafted length of
(N.times.L), placing the inelastic functional member substantially
parallel to and in contact with the drafted length of the first
elastic member, and, thereafter, covering, twisting or wrapping in
turns the composite covering about the drafted first elastic member
and the inelastic functional member. The composite covering may be
wrapped in the relaxed state or under tension. In addition, the at
least one inelastic member of the composite covering may be wrapped
in turns about the second elastic member, or the at least one
inelastic member of the composite covering and the second elastic
member may be twisted together.
It also lies within the scope of the present invention to provide a
knit, woven or nonwoven fabric substantially constructed from
functional elastic composite yarns of the present invention. Such
fabrics may be used to form a wearable garment or other fabric
articles substantially.
It further lies within the scope of the present invention to
provide a novel means of forming loops (or bends) of the functional
fiber member at discrete locations along the length of the fiber
when such fiber is integrated into a knit, woven or nonwoven
fabric. Such embodiments can further include a means of dynamically
controlling such loops (for example, their size, bending angle,
position) via the stretch and recovery function of such fabric.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be more fully understood from the following
detailed description, taken in connection with the accompanying
drawings, which form a part of this application and in which:
FIGS. 1A and 1B show scanning electron micrographs(SEMs) of 100%
stainless steel in parallel to Lycra.RTM. yarn type T-162C, single
covered with a 22/7 dtex/7 filament flat nylon yarn twisted to the
"S" direction at 500 turns per meter (tpm) in the relaxed state and
in the relaxed state after break respectively;
FIG. 2 shows scanning electron micrographs (SEMs) of 100% stainless
steel in parallel to Lycra.RTM. yarn type T-162C, double covered
with a 22/7 dtex/7 filament flat nylon yarn twisted to the "S" and
"Z" directions at 300 tpm and 200 tpm;
FIGS. 3A and 3B show scanning electron micrographs (SEMs) of 100%
stainless steel in parallel to Lycra.RTM. yarn type T-162C, double
covered with a nylon 44 dtex/20 filament textured yarn twisted to
both the "S" and "Z" directions at 500 tpm in the relaxed
state;
FIG. 4 shows a scanning electron micrograph (SEM) of 100% stainless
steel in parallel to Lycra.RTM. yarn type T-162C, single covered
with an elastified Lycra.RTM. yarn type T-902C (200 dtex, draft
5.2.times.) twisted to the "S" direction at 400 tpm;
FIGS. 5A and 5B show scanning electron micrographs (SEMs) of a
Raytela.RTM. plastic optical fiber in parallel to Lycra.RTM. yarn
type T-162C, single covered with a 22 dtex/7 filament flat nylon
yarn twisted to the "S" direction at 333 tpm in the stretched and
relaxed state, respectively;
FIGS. 6A and 6B show scanning electron micrographs (SEMs) of
Raytela.RTM. plastic optical fiber in parallel to Lycra.RTM. yarn
type T-162C, single covered with a 44 dtex/20 filament nylon yarn
twisted to the "S" direction at 100 tpm in the relaxed state;
FIG. 7 shows a scanning electron micrograph (SEM) of a Raytela.RTM.
plastic optical fiber in parallel to Lycra.RTM. yarn type T-162C,
single covered with an elastified Lycra.RTM. yarn type T-902C (200
dtex, draft 5.2.times.) twisted to the "S" direction at 400
tpm;
FIG. 8 shows stress-strain mechanical property data indicating
modulus definition for various high modulus functional fibers and
traditional textile fibers.
FIG. 9 shows a scanning electron micrographs (SEM) in the relaxed
state of a woven fabric produced in a Jaquard weaving loom type
T.I.S. TMF 100, in which an elastic fiber optic yarn containing a
Raytela.RTM. plastic optical fiber in parallel to Lycra.RTM. yarn
type T-162C, single covered with an elastified Lycra.RTM. yarn type
T-902C (200 dtex, draft 5.2.times.) twisted to the "S" direction at
400 tpm, was introduced in the weft direction and the warp directed
was constructed by inelastic cotton yarns;
FIGS. 10A and 10B show scanning electron micrographs (SEMs) of the
woven fabric shown in FIG. 9 that has been subjected to
vaporization under a Hoffmann HR2A steam press table for about 1
minute in the relaxed and stretched state, respectively;
FIGS. 11A and 11B show scanning electron micrographs (SEMs) at
different magnifications in the relaxed state of the woven fabric
shown in FIGS. 10A and 10B that has been further subjected to heat
setting through a Mathis laboratory heat stenter to about
180.degree. C. for about 2 minutes; and
FIG. 12 is a schematic diagram of an elastic composite yarn
according to the invention.
DETAILED DESCRIPTION OF THE INVENTION
In accordance with the present invention it has been found that it
is possible to produce an elastic composite yarn containing high
modulus or low bending fibers or yarns. Elastic composite yarns
falling within the scope of the present invention comprise a
composite core comprising: (a) an elastic core member (or "elastic
core"); and (b) an inelastic functional core member, wherein the
composite core is surrounded by at least one composite
covering.
The elastic core member has a predetermined relaxed unit length (L)
and a predetermined drafted length of (N.times.L), where N is a
number, preferably in the range from about 1.0 to about 8.0,
representing the draft applied to the elastic member. The inelastic
functional core member has a fixed length of (N.times.L).
Elastic composite yarns falling within the scope of the present
invention further include at least one composite covering. The
composite covering includes: (i) at least one elastic covering
member; and (ii) at least one inelastic covering member surrounding
the elastic covering member. The composite covering has a relaxed
length that is equal to or greater than the drafted length of the
elastic core member, such that substantially all of an elongating
stress imposed on the composite yarn is carried by the elastic core
member and the elastic covering member.
The Elastic Core Member
The elastic core member may be implemented using one or a plurality
(i.e., two or more) of filaments of an elastic yarn, such as that
spandex material sold by INVISTA North America S.ar.I. (Wilmington,
Del., USA, 19880) under the trademark LYCRA.RTM..
The drafted length (N.times.L) of the elastic core member is
defined to be that length to which the elastic member may be
stretched and return to within about five percent (5%) of its
relaxed (stress free) unit length L. More generally, the draft (N)
applied to the elastic core member is dependent upon the chemical
and physical properties of the polymer comprising the elastic cure
member and the covering and textile process used. In the covering
process for elastic members made from spandex yarns a draft of
typically is between about 1.0 and about 8.0, and most preferably
about 1.2 to about 5.0
Alternatively, synthetic bicomponent multifilament textile yarns
may also be used to form the elastic core member. The synthetic
bicomponent filament component polymers are thermoplastic, more
preferably the synthetic bicomponent filaments are melt spun, and
most preferably the component polymers are selected from the group
consisting of polyamides and polyesters.
A preferred class of polyamide bicomponent multifilament textile
yarns are those nylon bicomponent yarns which are self-crimping,
also called "self-texturing" These bicomponent yarns comprise a
component of nylon 66 polymer or copolyamide having a first
relative viscosity and a component of nylon 66 polymer or
copolyamide having a second relative viscosity, wherein both
components of polymer or copolyamide are in a side-by-side
relationship as viewed in the cross section of the individual
filament. Self-crimping nylon yarn such as the yarn sold by INVISTA
North America S.a.r.I. under the trademark TACTEL.RTM. T-800.TM. is
an especially useful bicomponent elastic yarn.
The preferred polyester component polymers include polyethylene
terephthalate (PET), polytrimethylene terephthalate (PTT) and
polytetrabutylene terephthalate. The more preferred polyester
bicomponent filaments comprise a component of PET polymer and a
component of PTT polymer. Both components of the filament can be in
a side-by-side relationship as viewed in the cross section of the
individual filament. An especially advantageous filament yarn
meeting this description is that yarn sold by INVISTA North America
S.ar.I. under the trademark T-400.TM. Next Generation Fiber. The
covering process for elastic members from these bicomponent yarns
involves the use of less draft than with spandex.
Typically, the draft for both polyamide or polyester bicomponent
multifilament textile yarns is between about 1.0 and about 5.0.
The Functional Core Member
The term "functional core member" refers to one or more fibers that
has at least one functionality or exhibits at least one property
that extends beyond mechanical properties commonly associated with
textile fibers. Functionalities or properties associated with such
members can, for example, include fiber optic data transmission,
dielectric high frequency applications (i.e., those using glass
and/or silica fibers), activity under electrical, optical or
magnetic fields, ability to convert energy from one form of energy
to another, and sensory, monitoring or actuation applications.
The functional core member may, for example, be selected from the
family of low bending modulus fibers, including stainless steel
fiber, stainless steel yarn, conductive metallized aramid fibers,
Plastic Optical Fiber (POF), and silica or glass optical fibers.
The inelastic functional core member may, for example, have a force
to break of greater than 2N in an elongation limit of less than 20%
or a yield point of greater than 2N in an elongation limit of less
than 20%.
The functional core member can further include: piezoelectric
fibers from polymers (e.g., polyamide 7, polyamide 11), or from
ceramic fiber composites; electrostrictive polymers;
electrostrictive elastomers, ferroelectric fibers; magnetostrictive
polymers or fiber composites; photonics fibers and nanocomposite
fibers; thermoresponsive (e.g., shape memory wires of polymers or
metal alloys); photoluminescent and electrochromic fibers; and
light sensitive liquid crystal containing fibers
In its most basic form, the functional core member comprises one or
a plurality (i.e., two or more) strand(s) of functional fibers.
In an alternative form, the functional core member comprises a
synthetic polymer yarn having one or more functional fibers(s)
thereon. Suitable synthetic polymer yarns are selected from among
continuous filament nylon yarns (e.g., from synthetic nylon
polymers commonly designated as N66, N6, N610, N612, N7, N9),
continuous filament polyester yarns (e.g., from synthetic polyester
polymers commonly designated as PET, 3GT, 4GT, 2GN, 3GN, 4GN),
staple nylon yarns, or staple polyester yarns. Such composite
functional yarns may be formed by conventional yarn spinning
techniques to produce composite yarns, such as plied, spun or
textured yarns.
Composite Covering
The composite covering of the present invention comprises an
elastic covering member and an inelastic covering member around or
surrounding the elastic covering member. The length of the
composite covering should be greater than, or equal to, the drafted
length (N.times.L) of the elastic core member.
The elastic covering member may be comprised of any of the
materials that can be used to for the elastic core member,
The inelastic covering member may be selected form nonconducting
inelastic synthetic polymer fiber(s) or from natural textile fibers
like cotton, wool, silk and linen. These synthetic polymer fibers
may be continuous filament or staple yarns selected from
multifilament flat yarns, partially oriented yarns, textured yarns,
bicomponent yarns selected from nylon, polyester or filament yarn
blends.
Optionally, the inelastic covering member may be a functional yarn
with a tensile strength or less than 4N or a yield point of less
4N. Such functional yarns can include yarns with electrical or
optical properties, such as a metal wire.
The inelastic covering member is preferably nylon. Nylon yarns
comprised of synthetic polyamide component polymers such as nylon
6, nylon 66, nylon 46, nylon 7, nylon 9, nylon 10, nylon 11, nylon
610, nylon 612, nylon 12 and mixtures and copolyamides thereof are
preferred. In the case of copolyamides, especially preferred are
those including nylon 66 with up to 40 mole percent of a
polyadipamide wherein the aliphatic diamine component is selected
from the group of diamines available from INVISTA North America S.a
r.I., (Wilmington, Del., USA, 19880) under the respective
trademarks DYTEK A.RTM. and DYTEK EP.RTM..
Making the inelastic covering member from nylon renders the
composite yarn dyeable using conventional dyes and processes for
coloration of textile nylon yarns and traditional nylon covered
spandex yarns.
If the inelastic covering member is polyester, the preferred
polyester is either polyethylene terephthalate (2GT, a.k.a. PET),
polytrimethylene terephthalate (3GT, a.k.a. PTT) or
polytetrahutylene terephthalate (4GT). Making the inelastic
covering member from polyester multifilament yarns also permits
ease of dyeing and handling in traditional textile processes.
The relative amounts of the functional core member and the
composite covering are selected according to ability of the elastic
core member to extend and return substantially to its unstretched
length (that is, undeformed by the extension) and according to the
functional properties of the functional core member. As used herein
"undeformed" means that the elastic core member returns to within
about +/- five percent (5%) of its relaxed (stress free) unit
length L.
It has been found that any of the traditional textile process for
single covering, double covering, air jet covering, entangling,
twisting or wrapping of elastic filaments and materials useful as
functional filaments with materials useful in the composite
covering is suitable for making the functional elastic composite
yarn according to the invention.
In most cases, the order in which the composite core is surrounded
by or covered by the composite covering is immaterial for obtaining
an elastic composite yarn. A desirable characteristic of these
functional elastic composite yarns of this construction is their
stress-strain behavior. For example, under the stress of an
elongating applied force, the composite covering, disposed about
the composite core in multiple wraps (typically from one turn (a
single wrap) to about 10,000 turns), is free to extend without
strain due to the external stress.
If the composite yarn is stretched near to the break extension of
the elastic core member, the composite covering is available to
take a portion of the load and effectively preserve the elastic
core member and the functional core member and prevent them from
breaking. The term "portion of the load" is used herein to mean any
amount from 1 to 90 percent of the load, and more preferably 10% to
80% of the load; and most preferably 25% to 50% of the load.
The composite core may optionally be sinuously wrapped by the
composite covering. Sinuous wrapping is schematically represented
in FIG. 12, where an elastic member 40, e.g., a LYCRA.RTM. yarn, is
wrapped with an inelastic covering member 10, e.g., nylon, in such
a way that the wraps are characterized by a sinuous period (P).
Specific embodiments and procedures of the present invention will
now be described further, by way of example, as follows.
Test Methods
Measurement of Fiber and Yarn Stress-Strain Properties
Fiber and Yarn Stress-Strain Properties were determined using a
dynamometer at a constant rate of extension to the point of
rupture. The dynamometer used was that manufactured by Instron
Corp, 100 Royall Street, Canton, Mass., 02021 USA.
The specimens were conditioned to about 22.degree. C. .+-. about
1.degree. C. and about 60% .+-. about 5% R.H. The test was
performed at a gauge length of about 5 cm and crosshead speed of
about 50 cm/min. Threads measuring about 20 cm were removed from
the bobbin and let relax on a velvet board for at least 16 hours in
air-conditioned laboratory. A specimen of this yarn was placed in
the jaws with a pre-tension weight corresponding to the yarn dtex
so as not to give either tension or slack.
Measurement of Fabric Stretch
Fabric stretch and recovery for a stretch woven fabric was
determined using a universal electromechanical test and data
acquisition system to perform a constant rate of extension tensile
test. The system used was that from Instron Corp, 100 Royall
Street, Canton, Mass., 02021 USA.
Two fabric properties were measured using this instrument: (1)
fabric stretch and (2) fabric growth (deformation). The available
fabric stretch was measured as the amount of elongation caused by a
specific load between 0 and about 30 Newtons and expressed as a
percentage change in length of the original fabric specimen as it
was stretched at a rate of about 300 mm per minute. The fabric
growth was measured as the unrecovered length of a fabric specimen
which had been held at about 80% of available fabric stretch for
about 30 minutes then allowed to relax for about 60 minutes. Where
about 80% of available fabric stretch was greater than about 35% of
the fabric elongation, this test was limited to about 35%
elongation. The fabric growth was then expressed as a percentage of
the original length.
The elongation or maximum stretch of stretch woven fabrics in the
stretch direction was determined using a three-cycle test
procedure. The maximum elongation measured was the ratio of the
maximum extension of the test specimen to the initial sample length
found in the third test cycle at load of about 30 Newtons. This
third cycle value corresponds to hand elongation of the fabric
specimen. This test was performed using the above-referenced
universal electromechanical test and data acquisition system
specifically equipped for this three-cycle test.
EXAMPLES
Reference numerals present in the discussion of the Examples refer
to the reference characters used in the accompanying
drawing(s).
Comparative Example 1
A 156 decitex (dtex) Lycra.RTM. yarn type T-162C was drafted by
3.8.times. its relaxed length, and fed in parallel to a 100%
stainless steel yarn through a yarn covering I.C.B.T. machine model
G307. The 100% stainless steel yarn was an endless multifilament
yarn grade 316L consisting of two twisted threads with 275
filaments per thread and with a filament size of 12 obtained from
Sprint Metal (France). This core composite yarn (consisting of
Lycra.RTM. and stainless steel yarn) was single covered with a 22
dtex/7 filament flat nylon yarn twisted to the "S" direction at 500
tpm (turns per meter of drafted Lycra.RTM.). This yarn structure 10
is shown in FIG. 1A, with the Lycra.RTM. yarn 12 and stainless
steel yarn 14 covered with the nylon yarn 16. As the yarn 10 is
stretched, nylon cannot support the elastification and it breaks,
as shown in FIG. 1B.
Comparative Example 2
A core composite yarn of Lycra.RTM. and stainless steel yarn as in
Comparative Example 1 was double covered with a 22 dtex/7 filament
flat nylon yarn twisted to the "S" direction at 300 tpm (turns per
meter of drafted Lycra.RTM.) and to the "Z" direction at 200 tpm.
This yarn structure 20 is shown in FIG. 2, with the Lycra.RTM. yarn
12 and stainless steel yarn 14 covered by the nylon 16. Despite the
fact that the yarn 20 was covered to a higher degree compared to
Comparative Example 1 of the invention, as the yarn 20 is
stretched, nylon cannot support the elastification and it
breaks.
Comparative Example 3
A covered yarn was produced as in Comparative Example 2, except it
was twisted at 500 tpm in both the "S" and the "Z" directions. As
the yarn is stretched, nylon cannot support the elastification and
it breaks.
Comparative Example 4
A covered yarn was produced as in Comparative Example 3, except
that the nylon yarn used was a 44 dtex/20 filament textured yarn.
The structure of this yarn 30 is shown in FIGS. 3A and 3B. Although
a stronger nylon yarn 36 was used compared to Comparative Example
3, as the yarn 30 is stretched, nylon cannot support the
elastification and it breaks.
Example 1
A covered yarn was produced in a manner similar to that of
Comparative Examples 1-4, except that the core composite yarn was
single covered with an elastified yarn twisted to the "S" direction
at 400 tpm. The elastified yarn was a double covered Lycra&
yarn (type T-902C, 200 dtex, draft 5.2.times.). The structure of
this yarn 40 is shown in FIG. 4, with Lycra.RTM. yarn 42 and
stainless steel yarn 44 covered by elastified yarn 46. As shown in
FIG. 4, this yarn 40 presents a structure at the relaxed state
comprising of straight segments, where the covered yarn holds the
core composite yarn in the stretched state, and of loops of
stainless steel. As the yarn 40 is stretched, the loops of
stainless steel yarn tend to stretch parallel to the Lycra.RTM.
core providing a totally stretched yarn that remains intact during
stretching. This yarn can be further processed by standard textile
processes.
Comparative Example 5
A 156 decitex (dtex) Lycra.RTM. yarn type T-162C was drafted by
3.8.times. its relaxed length, and fed in parallel to a plastic
optical fiber through a yarn covering I.C.B.T. machine model G307.
The plastic optical fiber was type Raytela.RTM. from Toray of 610
dtex that comprised a fluorinated polymer clad and polymethyl
methacrylate core. This core composite yarn was single covered with
a 22 dtex/7 filament flat nylon yarn twisted to the "S" direction
at 333 tpm (turns per meter of drafted Lycra.RTM.). This yarn
structure 50 is shown in FIG. 5B, with Lycra.RTM. yarn 52 and
plastic optical fiber 54 covered by nylon yarn 56. This structure
50 creates large loops of the optical fiber 54 up to a few cm in
diameter during relaxing, as shown in FIG. 5B. As the yarn 50 is
stretched, nylon cannot support the elastification and it breaks,
as shown in FIG. 5A.
Comparative Example 6
A covered yarn was made according to Comparative Example 5, except
that it was single covered with a stronger nylon yarn (44 dtex/20
filaments) twisted to the "S" direction at 100 tpm. The structure
of this yarn 60 is shown in FIGS. 6A and 6B, with Lycra.RTM. yarn
62 and plastic optical fiber 64 covered by nylon 66. The yarn 60
consists of straight parts as shown and loops of the optical fiber
formed during relaxing the yarn. These loops can be as large as a
few cm diameter so as to prohibit further processing of this yarn.
As the yarn is stretched the nylon yarn breaks.
Example 2
A covered yarn based on polymer optical fiber was formed as in
Comparative Examples 5 and 6, except that the composite core yarn
(consisting of Lycra.RTM. and optical fiber) was single covered
with an elastified yarn twisted to the "S" direction at 400 tpm.
The elastified yarn was a double covered Lycra.RTM. yarn (type
T-902C, 200 dtex, draft 5.2.times.). The structure of this yarn 70
is shown in FIG. 7, with Lycra.RTM. yarn 72 and plastic optical
fiber 74 covered by nylon 76. This yarn is composed of straight
sections and small loops of optical fiber. As the yarn stretches,
the loops of optical fiber straighten out with no break of the
composite yarns, providing for a yarn that is processable by
textile processes.
Example 3
A woven fabric 90 was produced in a Jaquard weaving loom type
T.I.S. TMF 100. Elastic Fiber Optic Yarn of Example 2 was
introduced in the weft direction of the fabric construction. The
warp direction was constructed solely by inelastic cotton yarns 98.
The fabric construction made was satin 16 to allow for maximum
space between the fiber optic and the crossing warp yarns. The
optical fibers introduced this way form loops of plastic optical
fiber 94 that extend outside of the fabric, as shown in FIG. 9. In
this case the fabric has limited stretch, for as the fabric is
stretched the loops are slightly shortened but not to a complete
extension.
Example 4
The fabric of Example 3 was subjected to vaporization under a
Hoffmann HR2A steam press table for about 1 min. The woven fabric
was substantially shrunk, as caused by the influence of the elastic
fiber optic yarns. In this state, the fabric 100 developed a
substantial stretch and recovery function. In the relaxed state,
this resulted in an increased size of the fiber optic 94 loops
compared to the features observed in Example 3, as shown in FIG.
10A. In the stretch state, the loops were totally flattened out
resulting in a total flat surface, as shown in FIG. 10B. Thus, by
controlling the stretch and recovery of the fabric, there is a
control of the magnitude of the fiber optic loop bending within the
textile structure.
Example 5
The fabric of Example 4 was subjected to heat setting through a
Mathis laboratory heat stenter to about 180.degree. C. for about 2
min. It was observed that the fabric 110 became totally rigid, and
the fiber optic 94 loops totally flattened out as to create a flat
fabric surface FIGS. 11A and B. It is thus possible, by controlling
the heating of selecting parts of the fabric, to enforce
straightening of the fiber optic loops, and therefore control of
the fabric areas that can include loops or straight elements of
fiber optic. This can introduce an additional degree of freedom
compared to control induced by the weaving construction.
The examples are for the purpose of illustration only. Many other
embodiments failing within the scope of the accompanying claims
will be apparent to the skilled person.
* * * * *